Field of the Invention
The present invention relates to a light controlling apparatus and a method of fabricating the same.
Description of the Related Art
In recent years, as the world entered the information age, the field of display devices for processing and displaying information has grown rapidly. Thus, various display devices have been developed and have drawn attention.
Specific examples of display devices include a Liquid Crystal Display (LCD) device, a Plasma Display Panel (PDP) device, a Field Emission Display (FED) device, and an Organic Light Emitting Diode (OLED). Such displays demonstrate excellent performance, such as thinning, weight lightening, and low power consumption. Thus, currently, application fields of the display device continue to increase. In particular, the display device has been used as a user interface in most electronic devices or mobile devices.
Further, in recent years, a transparent display device which enables a user to see an object or an image positioned on the opposite side through a display device has been actively studied.
The transparent display device has advantages in terms of space efficiency, interior decoration, and design. Further, the transparent display device can be applied to various fields. The transparent display device can resolve spatial and visual constraints of conventional electronic devices by realizing a display device capable of recognizing information, processing information, and displaying information in a transparent electronic device. The transparent display device can be used in a smart window, and the smart window can be applied to be used in a smart home or smart vehicle.
Particularly, an LCD may be realized as a transparent display device using an edge-type backlight, but a transparent display device using the LCD exhibits a very low transmittance ratio. Also, the transparent display device using the LCD has a disadvantage in that transparency is reduced by a polarizer used for realizing black and outside visibility is negatively affected as well.
Further, a transparent display device using an OLED has higher power consumption than the transparent display device using an LCD. Also, a transparent display device has difficulty in expressing true black, but does not have a problem with a contrast ratio in a dark environment. However, it has a disadvantage of reduction in a contrast ratio in a normal environment with light.
Therefore, in order to realize a transmissive mode and a light shielding mode, there has been suggested a method of using polymer dispersed liquid crystal (PDLC) or polymer networked liquid crystal (PNLC) formed into a single layer with a light controlling apparatus of the transparent display device using an OLED. The polymer dispersed liquid crystal (PDLC) or polymer networked liquid crystal (PNLC) formed into a single layer can be formed by mixing a monomer and a liquid crystal and irradiating ultraviolet (UV) rays to the mixture.
Particularly, the polymer dispersed liquid crystal (PDLC) has a structure in which a liquid crystal is formed within a polymer, and the polymer networked liquid crystal (PNLC) has a structure in which a polymer is distributed in a network structure on a liquid crystal.
If an electric field is applied to the polymer dispersed liquid crystal (PDLC) or polymer networked liquid crystal (PNLC), an alignment of the liquid crystal is changed, and, thus, light incident from the outside can be scattered or transmitted. That is, a device using the polymer dispersed liquid crystal (PDLC) or polymer networked liquid crystal (PNLC) can scatter or transmit light without a polarizer, and, thus, can be used as a light controlling apparatus of a transparent display device.